ERBB2 and breast cancer: In HER2+ BC patients who received a neoadjuvant treatment (chemotherapy with trastuzumab), those who were non-responsive had lower α-diversity, low levels of Lachnospiraceae, Prevotellaceae, Actinobacteria (Bifidobacteriaceae), Turicibacteriaceae, and Desulfovibrio, and more Bacteroides than patients who achieved a pathological complete response [11,16].